在群体水培条件下,采用遗传背景相似的染色体单片段代换系114个水稻株系为供试材料,依据成熟期单株吸氮量和单株籽粒产量两个性状进行聚类,将供试群体分为6种类型,并按单株吸氮量从低到高排序分为A、B、C、D、E和F类。结果表明:1)供试群体单株吸氮量差异较大,变幅为0.32 g~0.91 g,最大值是最小值的2.85倍。2)吸氮量和氮素籽粒生产效率均是影响产量的重要因素,但前者对产量的正向贡献度显著大于后者。3)随着吸氮量的增加,产量总体呈上升趋势。但吸氮量类型与产量类型并不完全吻合,高吸氮量仅是产量提高的重要基础,产量可能还受到其他因素的影响。4)不同类型间遗传群体株系活性性状(总吸收面积、活跃吸收面积和根系活力)差异较小,根系形态性状(根总长、根干质量、最长根长、众数根长)及冠根比差异显著,氮高吸高产型水稻单株不定根总长、单株根干质量、最长根长、众数根长、冠根比显著大于氮低吸低产型水稻。5)综合相关分析、主成分分析和通径分析的结果,影响染色体单片段代换系水稻遗传群体株系氮素高效吸收主要根系性状为单株根干质量、抽穗期冠根比、最长根长和单株不定根总长。通过遗传改良根系的形态性状可实现氮素吸收能力的显著提高。

To investigate the relationship between root traits and nitrogen accumulation in rice cultivars, a total of 114 chromosome single segment substitution lines (CSSSLs) were solution-cultured in 2010 and 2011. On the basis of nitrogen accumulation per plant and yield per plant at maturity, the CSSSLs were clustered by MinSSw method into six types (namely A,B,C,D,E and F by nitrogen accumulation per plant from low to high). The results shows that: 1)There was a significant difference among all tested lines in N accumulation per plant, the variation ranged from 0.32 g to 0.91 g. The highest N accumulation was 2.58 folds of the lowest. 2)Both N accumulation and nitrogen use efficiency for grain production were important contributors to yield formation, but the former exhibited higher contribution. With higher nitrogen accumulation, grain yield tended to increase, but nitrogen accumulation types and grain yield types were not always associated. 3)Higher nitrogen accumulation is an important basis of higher yield, but yield was also affected by other factors. 4)The differences in root activity traits (including the total root absorption area, the root active absorption area and the root activity) among rice cultivars were limited, but the root morphological traits(including total length of adventitious roots, root dry weight, the maximum root length and plural root length) and the ratio of shoot to root showed significant differences. The total length of adventitious roots per plant, root dry weight per plant, the maximum root length, plural root length and the ratio of shoot to root of higher nitrogen efficiency and yield types were significantly larger than those of lower nitrogen efficiency and yield types. 5) Correlation analysis, principal component analysis and path analysis revealed that main traits influencing nitrogen accumulation in the rice population were root dry weight per plant, the ratio of shoot to root at heading stage, the maximum root length and total length of adventitious roots per plant. Improving the root morphological traits through genetic approaches might significantly enhance nitrogen accumulation efficiency in rice plants.